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McDonald, K. T.

Paper Title Page
MOPC093 Experimental Study of Radiation Damage in Carbon Composites and Graphite Considered as Targets in the Neutrino Super Beam 280
 
  • N. Simos, H. G. Kirk
    BNL, Upton, Long Island, New York
  • K. T. McDonald
    PU, Princeton, New Jersey
 
  Carbon composites have been of primary interest as materials of choice for a multi-MW neutrino superbeam which desires low-Z pion production target. Beam on target experiments conducted at BNL made the case stronger in their favor, as compared to graphite, by demonstrating their excellent shock resistance which is directly linked with their extremely low thermal expansion. Since target survivability also depends on resistance to prolonged radiation, a series of irradiation damage studies on carbon composites and graphite were launched. While carbon composites at moderate doses exhibited interesting behavior of damage reversal through thermal annealing, at higher dose levels of peak proton fluences >5x1020 protons/cm2 they exhibited serious structural degradation. The experimental study also showed that graphite suffered similar damage when subjected to same fluence level. The paper discusses the findings of the experimental studies focusing on these materials and attempts to explain their structural degradation observed under high proton fluences given the excellent survivability record, especially of graphite, under high neutron fluences in nuclear reactor settings.

Work performed under the auspices of the US DOE.

 
MOPC094 Irradiation Effects on the Physio-mechanical Properties of Super-alloys Characterized by Low Thermal Expansion 283
 
  • N. Simos, H. G. Kirk
    BNL, Upton, Long Island, New York
  • K. T. McDonald
    PU, Princeton, New Jersey
  • N. V. Mokhov
    Fermilab, Batavia, Illinois
 
  In an effort to address the limitations on high power accelerator target performance prompted by the elevated dose levels and the associated irradiation damage, an experimental study has been undertaken to evaluate the potential applicability of super alloys characterized by low thermal expansion over certain thermal regimes. The intriguing properties associated with materials such as super-Invar and the “gum” metal (Ti-12Ta-9Nb-3V-6Zr-O) are observed in their un-irradiated state. Irradiations were performed using the 200 MeV protons of the BNL Linac and/or a neutron flux generated by the stopping of the primary 112 MeV protons upstream of the exposed super-alloys. The paper presents the post-irradiation analysis results which reveal interesting damage reversal by the super-invar and unexpected low threshold of radiation resistance by the “gum” metal.

Work performed under the auspices of the US DOE.

 
MOPC087 The MERIT (nTOF-11) High Intensity Liquid Mercury Target Experiment at the CERN PS 262
 
  • I. Efthymiopoulos, A. Fabich, A. Grudiev, F. Haug, J. Lettry, M. Palm, H. Pernegger, R. R. Steerenberg
    CERN, Geneva
  • J. R.J. Bennett
    STFC/RAL/ISIS, Chilton, Didcot, Oxon
  • O. Caretta, P. Loveridge
    STFC/RAL, Chilton, Didcot, Oxon
  • A. J. Carroll, V. B. Graves, P. T. Spampinato
    ORNL, Oak Ridge, Tennessee
  • H. G. Kirk, H. Park, T. Tsang
    BNL, Upton, Long Island, New York
  • K. T. McDonald
    PU, Princeton, New Jersey
  • N. V. Mokhov, S. I. Striganov
    Fermilab, Batavia, Illinois
 
  The MERIT (nTOF-11) experiment is a proof-of-principle test of a target system for high power proton beams to be used as a front-end for a neutrino factory complex or a muon collider. The experiment took data in autumn 2007 using the fast extracted beam from the CERN Proton Synchrotron (PS) with a maximum intensity of about 30TP per pulse. The target system, based on a free mercury jet, is capable of intercepting a 4-MW proton beam inside a 15-T magnetic field Such a field is required to capture the low-energy secondary pions which will provide the source of the required intense muon beams. Particle detectors have been installed around the target setup in order to measure the secondary particle flux out of the target and probe cavitation effects in the mercury jet when hit with variable intensity beams. The data analysis is ongoing: the results presented at this conference will demonstrate the validity of the liquid mercury target concept.

For the MERIT collaboration.

 
WEPP170 A 15-T Pulsed Solenoid for a High-power Target Experiment 2889
 
  • H. G. Kirk
    BNL, Upton, Long Island, New York
  • J. R.J. Bennett
    STFC/RAL/ISIS, Chilton, Didcot, Oxon
  • I. Efthymiopoulos, A. Fabich, F. Haug, H. Pereira
    CERN, Geneva
  • K. T. McDonald
    PU, Princeton, New Jersey
  • P. H. Titus
    MIT/PSFC, Cambridge, Massachusetts
 
  The MERIT experiment, which ran at CERN in 2007, is a proof-of-principle test for a target system that converts a 4-MW proton beam into a high-intensity muon beam for either a neutrino factory complex or a muon collider. The target system is based on a free mercury jet that intercepts an intense proton beam inside a 15-T solenoidal magnetic field. Here, we describe the design and performance of the 15-T, liquid-nitrogen-precooled, copper solenoid magnet.  
WEPP169 The MERIT High-power Target Experiment at the CERN PS 2886
 
  • H. G. Kirk, H. Park, T. Tsang
    BNL, Upton, Long Island, New York
  • J. R.J. Bennett
    STFC/RAL/ISIS, Chilton, Didcot, Oxon
  • O. Caretta, P. Loveridge
    STFC/RAL, Chilton, Didcot, Oxon
  • A. J. Carroll, V. B. Graves, P. T. Spampinato
    ORNL, Oak Ridge, Tennessee
  • I. Efthymiopoulos, A. Fabich, F. Haug, J. Lettry, M. Palm, H. Pereira
    CERN, Geneva
  • K. T. McDonald
    PU, Princeton, New Jersey
  • N. V. Mokhov, S. I. Striganov
    Fermilab, Batavia, Illinois
 
  The MERIT experiment was designed as a proof-of-principle test of a target system based on a free mercury jet inside a 15-T solenoid that is capable of sustaining proton beam powers of up to 4MW. The experiment was run at CERN in the fall of 2007. We describe the results of the tests and their implications.